DFU_DNLOAD request commands

AN3156

20/26

DocID017068 Rev 4

The Erase command is effectively executed only when a DFU_GETSTATUS request is

issued by the host. If the status returned by the device is not dfuDNBUSY, then an error has

occurred.

A second DFU_GETSTATUS request is needed to check if the command has been correctly

executed. If the received page address is wrong or unsupported, the device status is then

(Status = dfuERROR, State = errTARGET). If the Flash Read Protection is active, then the

device returns the status (Status = dfuERROR, State = errVENDOR) and the erase

operation is ignored by the device.

The allowed Erase page addresses are internal Flash memory addresses.

Note:

No error is returned when performing Erase operations on write protected sectors.

Figure 9. Erase command: Device side

5.4

Read Unprotect command

The Read Unprotect command is selected when wValue = 0 and the first byte of the buffer

sent by the host is 0x92. The buffer length should be only 1 byte (only the command byte).

The host sends a DFU_DNLOAD request with the above parameters to remove the read

protection of the internal Flash memory.

The device receives the byte as follows:

After sending a Read Unprotect command, the host has to send a DFU_GETSTATUS

request.

Byte 1:

0x92

- Read Unprotect command